1. Field of the Invention
The present invention relates to a stopper for vials for pharmaceutical injection preparations and the like.
2. Description of the Prior Art
In recent years, freeze-dried preparations are frequently used as medicinal drugs for injection. FIGS. 1 to 3 show a conventional stopper which is used for vials for containing such preparations, wherein FIG. 1 is a front view of the same, FIG. 2 is a side elevation of the same, and FIG. 3 is a bottom view of the same.
The stopper is partially fitted into the opening of a vial (V) filled with the medicinal solution (S) to be freeze-dried as shown in FIG. 4. The solution within the vial is freeze-dried in this state, and the vial is evacuated or the air in the interior of the vial is replaced by nitrogen gas. Since the stopper must be held stably and partially fitted in during the freeze-drying step and the nitrogen gas replacement step, the legs to be inserted into the opening of the vial are invariably elongated and adapted to have a large area of engagement with the inner wall surface of the vial opening portion.
Because the stopper is used for vials containing medicinal preparations for injection, it is deliberately washed, sterilized and dried before use. However, when a large quantity of stoppers are subjected to these treatments all together, the legs of the stopers are very likely to become entangled as seen in FIG. 5. If the stoppers are sterilized and dried with their legs thus entangled with one another, the legs are semi-permanently deformed by heating in the course of the treatment. Further if they are stored with entangled legs for a considerable period of time before use, semi-permanent deformation will also result.
When the stoppers to be fed to the partial fitting process include such deformed stoppers, the deformed stoppers are likely to jam the feed path, or it becomes impossible to use an automatic machine for this process.